Hybrid plasma-semiconductor devices

Abstract

A hybrid plasma-semiconductor phototransistor has been realized by substituting a plasma for the collector of an npn bipolar junction transistor. Designated as the plasma bipolar junction transistor (PBJT), this optoelectronic device relies on the correspondence between the properties of a low temperature, nonequilibrium plasma and those of the electron-hole plasma in an n-type semiconductor. Coupling electrons and holes in a semiconductor and electrons and ions in the gaseous plasma with a strong electric field yields a transistor with photosensitivity, gain, and a light-emitting collector whose radiative output can be modulated or switched using voltages that are less than 1 V. It has been found that the current gain of the transistor increases as a function of the increasing gas pressure and Vcc supplied to the test circuit. External illumination of the base region during operation increases the base current, confirming that the PBJT exhibits phototransistor properties. The utilization of the PBJT in an amplifier circuit has shown voltage gains up to 170 and power gains of nearly 80. A reduction in device dimensions shows promising results for eliminating observed hysteresis as well as increasing the operating frequency and gas pressure of the device.

In addition, a new robust silicon microplasma structure serving as a high-frame-rate, ultra-high-resolution plasma generator has been designed and built, and is currently undergoing preliminary testing. This new structure, designated as the dual junction microplasma (DJM) device, utilizes silicon pn junctions in a specific arrangement to generate plasma emission.